Preparation and analysis of tridirectionally anisotropic superhydrophobic surface with biomimetic wedge-shaped structure

A novel biomimetic wedge-shaped structure (BWSS) has been fabricated using nanosecond laser etching method. The BWSS as-processed exhibits superhydrophilicity (contact angle (CA) = 0(degrees)) and transforms to super hydrophobicity (CA > 160(degrees)) after chemical modification. Sliding angles (SAs) on the superhydrophobic surface show the tridirectional anisotropy: SAs in perpendicular anti outside radial direction (IAnti-RO) > SAs in perpendicular outside radial direction (IRO) > SAs in parallel direction (& Vert;). Mechanisms of tridirectional anisotropy are discussed in detail. The original phenomenon indicates the superhydrophobic surface with BWSS possesses excellent tridirectionally anisotropic wettability, which can provide enormous potential applications in microfluidic fields.